It is not entirely clear where the origins of Tetanurae are. Cryolophosaurus has been claimed as the first true member of the group, although this identification has been disputed and Cryolophosaurus now appears to be closer to the dilophosaurids). Even if Cryolophosaurus was a tetanuran, this leaves no true tetanuran fossils from the Triassic, when the group should have originated based on the presence of coelophysoids (if the old definition of Ceratosauria is used). This gives heavier validity to the more recent view of tetanurans and ceratosaurs sharing a common ancestor and forming a clade of advanced theropods together.